Dog

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Dog reproduction

As with most domesticated species, one of the first and strongest effects seen from selective breeding is, logically enough, selection for cooperation with the breeding process as directed by humans. In dogs, this takes the form of abolition of the pair bonding seen in wild canines, as well as the ability of female domestic dogs to come into estrus (also called in season or in heat) at any time of the year and usually twice a year; unlike undomesticated canine species where the females typically come into once season a year, usually in late winter, and bear one litter of young. Most bitches come into season for the first time between 6 and 12 months, although some larger breeds delay until as late as 2 years. Like most mammals, the age that a bitch first comes into season is mostly a function of her current body weight as a proportion of her body weight when fully mature, rather than age, with the different maturation rates of the various sizes of dogs accounting for this variation in age of first season. The amount of time between cycles varies greatly among different dogs, but a given dog's cycle tends to be consistent through her life. Dogs bear their litters roughly 9 weeks after insemination.

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An average litter consists of about six puppies, especially for breeds that have not strayed too far from their wild ancestors. However, litters of many more or only one or two puppies are also common. Some breeds have a tendency to produce very large litters. Since a mother can provide milk for only a few of those puppies, humans must assist in the care and feeding when the litter exceeds eight or so.

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Some breeds have been developed to emphasize certain physical traits beyond the point at which they can safely bear litters on their own. For example, the Bulldog often requires artificial insemination and almost always requires cesarean section for giving birth.

Related Topics:
Bulldog - Artificial insemination - Cesarean section

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Puppies often have characteristics that do not last beyond early puppyhood. For example, eyes are often blue when they first open but change to other colors as the puppy matures. As another example, Kerry Blue Terrier puppies have black coats when they are born and their distinctive "blue" color appears gradually as the puppy nears maturity. The ears of erect-eared breeds such as the German Shepherd Dog are softly folded at birth but straighten as the puppy grows; in cases where they fail to straighten on their own, owners sometimes opt for surgical intervention.

Related Topics:
Kerry Blue Terrier - German Shepherd Dog

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Dog experts advise that dogs not intended for further breeding should be spayed or neutered so that they do not have undesired puppies, which are often abandoned. Abandoned dogs who go feral are particularly dangerous; they lack the skills of wild canines at survival in the wild, as well as the genetic and learned fear of humans that keeps wild canines away from humans and their possessions, so they form predatory packs that attack livestock and occasionally also prove dangerous to humans. The overpopulation of unwanted dogs is so great that almost all dogs who end up in animal shelters are euthanized due to lack of space and resources. Spaying and neutering can also help prevent hormone-driven diseases such as breast cancer and prostate cancer, as well as undesired hormone-driven behaviors. Contrary to myth, it is not required for a female dog to either experience a heat cycle or have puppies before spaying, and likewise, a male dog does not need the experience of mating before neutering; these myths are responsible for numerous unnecessary health problems and unwanted puppies. Attempts by owners to carry on some particular admirable qualities of their dogs by breeding them usually fail. Dogs of mixed breed do not "breed true"; i.e., with a mixed breed dog the offspring may not carry characteristics found in a parent, or even shared by both parents. Similarly, but to a lesser extent, even with purebreed dogs sold as pets the offspring may not have the subtle best qualities of the parents; it may be necessary to go back to the high quality breeding stock and reproduce the original mating as closely as possible to reproduce the desired characteristics very closely. Of course, most owners who let their dogs reproduce will feel the offspring are superior; however, realistically speaking, the natural sentimental bias makes it just as likely that they would feel the same way about any dog they acquired, from the pound or elsewhere.

Related Topics:
Spay - Neuter - Feral - Livestock

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